In modern computing systems, a special management mode, sometimes referred to as a system management mode (SMM), is used for physical memory manipulation operations such as hot plug, error management, and so forth. Since the SMM code is running from the same physical memory in which these operations are performed, this arrangement is liable to Heisenberg's law, and may have issues where the memory backing SMM code has a flaw.
During hot plug operation, additional memory is dynamically added to a system. Typically to support a memory hot add feature efficiently, system firmware executes memory training code in this SMM so that an operating system (OS) can use the newly added memory module dynamically. However, this training introduces challenges, in that the code to perform this training needs to time-share/perform processor (e.g., central processing unit (CPU)) cycle-stealing to execute, which adversely impacts an active workload being handled by OS. Given typical restrictions imposed by the OS, there may be temporal limitations on a duration of SMM execution, which can undesirably impact performance and lengthen time required for completion of the memory training.